Washington (CNN) - Just days after taking office, Britain's new foreign secretary visited Washington on Friday, hailing the "unbreakable alliance" between the U.S. and Britain.

"The U.S. is without doubt the most important ally of the UK," William Hague said after lunch with Secretary of State Hillary Clinton. He welcomed President Barack Obama's description of the "extraordinary special relationship" between the two countries.

Hague was announced as Britain's foreign secretary this week after a coalition government was formed between Prime Minister David Cameron's Conservative Party and the Liberal Democrats.